Circuit boards having a flexible portion are known in the art and are particularly useful in various applications where flexing or folding of the circuit board is a requirement. Further, circuit boards having shield layers on opposing sides of the circuit board are known and find important use in applications where prevention of incidental radiation from the board and shielding of the board from external noise is required.
Providing one or two continuous shielding layers on surfaces of a circuit board necessarily limits or eliminates the board's ability to flex. This is particularly true where shield layers are deposited or formed directly on the circuit board substrate surfaces. Stress between the layers during flexing can lead to severance of the bond between shield layers and the circuit board, and a resultant decrease in shield efficiency and board performance.
The prior art fails to meet the demand for a truly flexible circuit board having shielding sufficient to meet strict incidental radiation specifications, such as those of the Federal Communications Commission (FCC) and International Special Committee on Radio Interference (CISPR/VDE).